1. Field of the Invention
This invention relates to an apparatus suited for field assembly of manufactured items, especially for use with ready to assemble, modular or knockdown upholstered furniture. This invention also relates to connectors comprising male fasteners that can be inserted into keyhole slots both to lock components together and to tighten the connection between the components to form a sturdy final assembly.
2. Description of the Prior Art
Knockdown, ready-to-assemble (RTA) or modular are terms employed to describe furniture in which components or subassemblies are manufactured, packaged and then shipped, with final assembly normally being left to the purchaser. The advantages of employing items of this type include the ability to reduce transportation costs as well as to pass the cost of final assembly to the purchaser. However, the disadvantages include: inferior quality associated with either inadequate stability or exposed exterior connectors that detract from the appearance; the limitations on aesthetic designs imposed by concealing connecting methods inside an upholstered item; and the inability to realize enough savings from reduced transportation costs and purchaser's assembly to overcome the extra manufacturing costs related to an RTA upholstered item.
The globalization of furniture manufacturing has magnified the importance of the cost of shipping finished product to a global retail market. The profitability and subsequent successful utilization of most RTA systems hinge upon the total savings from reduced transportation costs and assembly by purchaser being at least equal to and preferably greater than the extra costs of manufacturing an item employing an RTA system. The most successful knockdown, ready-to-assemble or modular furniture items tend to be products, such as tables, desks and chairs.
The primary advantage of shipping these items in an unassembled state is the large reduction of the cubic volume of the parts relative to the assembled item. Tables when assembled are mostly space. When the unassembled parts are packaged, there are significant savings in transportation costs which offset the extra expense of employing the extra RTA engineering and manufacturing costs. For example: a dining table 48″×48″×30″ equals about 40 cubic feet of shipping volume. The same table, (depending on its design) could easily be packaged in an unassembled state in a box 70% smaller, requiring 12 cubic feet of shipping. The difference of 28 cubic feet of shipping volume, at a cost of $2.00 per cubic foot, (current overseas container shipping costs), translates into an initial savings of $56.00 per table. The economical advantages of this smaller package are further increased if additional transportation and warehousing costs are considered.
It is much more difficult to reduce the cubic feet of an upholstered item of furniture because the volume required by the structure of the frame, the foam and cushions is significantly greater in proportion to the total volume of the assembled item in comparison to a table. Most RTA upholstered systems enhance the ability to handle the individual components for final delivery in tight quarters, but do not strategically address critical shipping logistics. The ability to break an upholstered item down into individual parts does not automatically translate into significantly reducing shipping costs. U.S. Pat. No. 5,678,897 is an example of a system that comprises components that can be shipped in an unassembled manner. However, this prior art approach does not appear to greatly reduce the volume in which this item can be shipped.
Tables and similar items which successfully employ RTA systems are generally made of solid components such as wood, metal and cast resin. The leg and support members by reason of the openness of the structure afford easy access for assembly. Upholstered furniture is however more difficult to fabricate by this method because the access to connecting fasteners hidden inside of the upholstered components is limited. In addition if accepted standards of quality and the performance of seating products which are subjected to the stress and constant movement of one or more person's full weight are to be achieved, the fasteners or connectors must be reliable and considerably stronger than those employed in lighter duty applications. Some upholstered furniture does employ fasteners or connectors for the final steps of assembly. For example, the backs of recliners are typically assembled to the base with co-operable metal fasteners. However, significant assembly of the other components are necessary, and even the final assembly of the recliner back is not normally considered to be a final assembly step, nor are the recliner bases and backs shipped separately. Modular sofas also commonly employ metal fasteners to prevent adjacent modular components from slipping apart, but the individual modular sofa units are typically fully manufactured in a factory, and the purpose of modularity is to allow the purchaser to arrange the modular components in different configurations. The connectors are primarily intended to stabilize the units that are positioned side by side. In each of these configurations almost all of the manufacturing is completed in a factory setting.
There have been suggestions for field assembly of upholstered furniture. U.S. Pat. No. 5,678,897 is one example of ready to assemble upholstered furniture. That device is an example of a device in which multiple special connectors are needed to attach sofa arms to a sofa back and to a sofa deck, and it is apparent that special attention to the manner in which cushions must be compressed prior to assembly is necessary, and it is an example in which special access to the interior of the components is necessary for assembly.
U.S. Pat. No. 6,267,446 and U.S. Pat. No. 6,981,747 are examples of similar approaches for fabricating an upholstered sofa or chair where the final assembly can be a field assembly. The approach adopted in these two patents and related patents is to provide a means for assembling a frame in the field, after which the frame is covered by preassembled cushions. This approach provides one method of packaging the components, prior to assembly, in a relatively small space to reduce the cost of shipping the components. However, it would appear that this approach is limited to certain styles because the design of the structural members out of OSB panels is so radically different from normal upholstery frame design. Further limitations stem from the utilization of preformed arm and back cushions and covers fitted over the frame after field assembly of the frame. It is not apparent that this approach could be adapted to upholstered furniture having the styles and designs that would appeal to many, if not most, customers, and this approach may not be applicable to higher style items.
U.S. Pat. No. 6,942,298 is another example in which sofa components can be assembled in the field to take advantage of shipping the sofa in pieces. It is suggested that the frames of that device can be assembled in the field and that a pliable material can be upholstered to the frame either before or after the frame is assembled. However it would appear that the type of upholstery would be limited by the need to access the interior of the components, and this issue does not appear to have been addressed.
Although keyhole slot configurations have been employed to connect furniture components, their use has primarily involved connection of panels and wooden member for desks, chairs, tables and items of this type. The advantages of keyhole slot configurations in both improving the structural stability and rigidity of upholstered furniture items, and at the same time reducing the space necessary to ship furniture items in a preassembled state does not appear to have been previously addressed.